U.S. patent number 4,731,908 [Application Number 07/007,966] was granted by the patent office on 1988-03-22 for apparatus for the scalding of carcasses.
This patent grant is currently assigned to Slagteriernes Forskningsinstitut. Invention is credited to Olaf Thorsen.
United States Patent |
4,731,908 |
Thorsen |
March 22, 1988 |
Apparatus for the scalding of carcasses
Abstract
An apparatus for the scalding of carcasses comprises a heat
insulated cabin (1) for the carcasses (3) and fans (4) with
appertaining air ducts (5) for the circulation of hot, humid air
past the carcasses being conveyed through the cabin. Fan supported
burners (6) and water atomizers (9) opening directly into the air
ducts are provided for maintaining the temperature and humidity of
the circulating air. The output of the burners (6) is adjusted
directly by temperature sensors placed in the circulating air,
while the water atomizers (9) are set for a constant output. The
adjustment can adapt itself quickly to changing load conditions so
that a constant condition is maintained in the cabin. The apparatus
has also one or more air discharge ducts (10) for the air supplied
to the cabin by the burners (6).
Inventors: |
Thorsen; Olaf (Olstykke,
DK) |
Assignee: |
Slagteriernes
Forskningsinstitut (Roskilde, DK)
|
Family
ID: |
8106825 |
Appl.
No.: |
07/007,966 |
Filed: |
December 12, 1986 |
PCT
Filed: |
April 11, 1986 |
PCT No.: |
PCT/DK86/00038 |
371
Date: |
December 12, 1986 |
102(e)
Date: |
December 12, 1986 |
PCT
Pub. No.: |
WO86/05952 |
PCT
Pub. Date: |
October 23, 1986 |
Foreign Application Priority Data
|
|
|
|
|
Apr 12, 1985 [DK] |
|
|
1643/85 |
|
Current U.S.
Class: |
452/74 |
Current CPC
Class: |
A22B
5/08 (20130101) |
Current International
Class: |
A22B
5/00 (20060101); A22B 5/08 (20060101); A22B
005/08 () |
Field of
Search: |
;17/47,14,15,11.2,51 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Abercrombie; Willie G.
Attorney, Agent or Firm: Fleit, Jacobson, Cohn &
Price
Claims
I claim:
1. An apparatus for the scalding of carcasses comprising:
heat insulated cabin means for housing the carcasses;
fan means for moving hot humid air through said cabin means;
water atomizer means for providing atomized water to said
cabin;
burner means for heating the atomized water and air;
and
air discharge duct means for discharging air supplied to said
cabin.
2. The apparatus according to claim 1 further comprising air duct
means for directing the hot humid air through said cabin means,
said air duct means communicating with said fan means, said burner
means and said water atomizer means.
3. The apparatus according to claim 1, further comprising
temperature sensor means for regulating the output of said burner
means.
4. The apparatus according to claim 2, wherein the water atomizer
means comprising atomizing nozzles and water pumps connected
thereto.
5. The apparatus according to claim 4, further comprising basin
means for collecting water, said basin means being placed under the
atomizing nozzles in the air ducts, and said basin means being
connected to the suction side of the water pumps.
6. The apparatus according to claim 4, wherein said air discharge
duct means are equipped with air/water heat exchangers having water
outlets, and wherein said water outlets are connected to the
suction side of the water pumps.
7. The apparatus according to claim 1, further comprising belt
conveyor means for carrying lying carcasses through the cabin.
8. The apparatus according to claim 7, wherein the belts of said
belt conveyor means further comprise perforated means for enabling
passage of humid air at right angles to the planes of the
belts.
9. The apparatus according to claim 8, wherein said belts are
nets.
10. The apparatus according to claim 1, further comprising sliding
bar means for conveying suspended carcasses through the cabin.
11. An apparatus according to claim 1, wherein said burner means is
selected from the group consisting of gas and oil burners.
Description
The present invention relates to an apparatus for the scalding of
carcasses comprising a heat insulated cabin for the carcasses and
fans with appertaining air ducts for the circulation of hot, humid
air past the carcasses which are conveyed through the cabin.
In bacon factories the carcasses are exposed to hot water or a hot,
humid air current for a suitable period until dead surface layers
and bristles have loosened. The parts can then be removed in a
machine by means of rotary beating straps.
When scalded by a hot air current, the carcasses are conveyed
through a cabin in which a vertical air current with a high
humidity and a temperature of 60.degree.-70.degree. C. is provided.
The aqueous vapour in the air is condensed as water droplets on the
rind surface of the carcasses, and heat is thus supplied to the
rind. After 6-10 minutes of treatment the surface layer and
bristles of the carcass have loosened sufficiently to be removed in
a machine.
In order to ensure uniform scalding of the rind surface it is
necessary to maintain the temperature and humidity of the
circulating air.
In a prior art apparatus steam is blown into the circulating air,
and immediately thereafter the air is passed along cooling elements
whereby the surplus humidity in the air is condensated into
floating water droplets. The carcasses are thus scalded in a mist
of hot water particles. The apparatus requires much energy because
large amounts of heat are lost through the cooling elements.
Another prior art apparatus uses electric heaters together with
steam to maintain a fixed temperature and air humidity, e.g. 85-95%
relative humidity. A humidity sensor and a temperature sensor
control the electric heaters and the steam supply. The steam
consumption is thus reduced but at the same time electric power is
required which normally is more expensive than fuel used in steam
generators.
Owing to the fact that the loading of the cabin is constantly
changing it has also appeared to be difficult to obtain a
satisfactory joint control of both temperature and humidity.
The present invention provides a scalding apparatus without the
abovementioned disadvantages. The apparatus according to the
invention is characterized in that it comprises burners and water
atomizers opening directly into air ducts, and one or more air
discharge ducts for the air supplied to the cabin by the
burners.
The apparatus according to the invention is advantageous in that
only one heat source is used which supplies the necessary amount of
heat directly, neither more nor less. The heat is utilized directly
for production of vapour and heating of the circulating air, which
means that the heat source is very cheap in operation.
By adjusting the burner output it is also possible to keep both
temperature and air humidity constant which results in a very
simple control.
In compliance with the invention, temperature sensors may thus be
placed in the circulating air having connected control units for
direct regulation of the burner output maintaining a constant
condition in the cabin.
According to the invention the water atomizers may comprise
atomizing nozzles and water pumps connected hereto, particularly
with a constant output.
In order to collect and re-use surplus water from the water
atomizers according to the invention a basin may be placed under
the atomizing nozzles in the air ducts, and the suction side of the
water pumps may be connected to this basin.
The air discharge ducts of the apparatus according to the invention
may be equipped with air/water heat exchangers, the water outlets
of which are connected to the suction side of the water pumps. In
this way the heat in the discharge gas may be used for preheating
of the water which is supplied to the pumps.
The apparatus according to the invention may be supplied with one
or more belt conveyor systems conveying lying carcasses through the
cabin. This embodiment has the advantage of not discolouring the
rind as is the case with scalding of suspended carcasses.
In order to produce a uniform scalding the belts of the system may
be designed with a considerable perforated area enabling the
passage of humid air at right angles to the belt planes. The belts
may be in the form of nets easily penetrated by the humid air.
The apparatus according to the invention may comprise a sliding bar
along which suspended carcasses are conveyed in the cabin. The
result is a simpler construction and maintenance than with the
above-mentioned belt conveyor system.
The invention is described in more detail in the following, with
reference to the drawings which show a section through three
different embodiments of a scalding apparatus for pig and sow
carcasses.
FIG. 1 shows a scalding cabin with a suspended carcass conveyed on
a sliding bar,
FIG. 2 a cabin with a lying carcass conveyed on a belt, and
FIG. 3 a corresponding cabin, but with three belts for conveying
the carcasses.
The embodiment of the apparatus shown in FIG. 1 is designed for the
scalding of approx. 160 carcasses per hour. It comprises a cabin 1,
approx. 15 meters long with heat insulated walls. A sliding bar 2
extends through the cabin along which suspended carcasses 3 are
conveyed by drivers not shown. A number of air circulation systems
is installed at intervals of approx. three meters seen in the
longitudinal direction of the cabin.
Each system consists of a fan 4 and an air duct 5 which guides the
air from the fan outlet to an opening at the bottom of cabin 1. An
opening in the wall of the air duct accommodates a burner 6 with a
fan in such a way that the combustion gas is supplied to the duct
5. A gas or oil burner is used. An air temperature sensor is fitted
in the interior of cabin 1 to regulate the burner output via a
control system.
A water pump 7 sucks water through a basin 8 at the bottom of the
duct 5 and pumps it through atomizing nozzles 9 placed in the
centre of the duct. The nozzles 9 and the pumps 7 are so
dimensioned that there will be a surplus of atomized water even at
maximum outputs of the burners.
At the top of cabin 1 air discharge ducts 10 are located which are
equipped with air/water heat exchangers 11. Demineralized water may
be supplied to the water side of each heat exchanger through a
valve 12 which is controlled by a level sensor in the basin 8. The
water preheated in the heat exchanger flows together with the
condensate drops of the heat exchanger through a tube to the basin
8 which supplies the water pump 7.
The cabin bottom holds a drain 13 for the removal of condensate
dripping from the suspended carcasses 3.
The apparatus works as follows:
Pig carcasses are moved along the sliding bar 2 and enter the cabin
1 through an air lock which keeps the hot, humid circulating air
inside the cabin. The air sweeps up along the sides of the
carcasses which are cooled to such an extent that condensate is
formed on the rind surface which is gradually scalded during the
passage of the carcasses through the cabin.
The cooled and dehumidified air sucked away by the fans 4 is heated
and re-humidified in the ducts 5 by means of the burners 6 and the
nozzles 9. The output of each burner is regulated automatically by
means of the temperature sensor, so that the air sweeping alongside
the carcasses maintains a constant condition, e.g. a temperature of
67.degree. C. and a relative humidity of 95-100%.
The air temperature may be controlled in each circulation system
independently of the temperatures in the adjacent circulation
system, for example so that a higher temperature is maintained in
the cabin inlet than in the outlet.
The embodiment shown in FIG. 2 is designed in a way similar to that
used in the apparatus shown in FIG. 1, but instead of the sliding
bar 2 it has a belt system 20 for conveying the carcasses in the
scalding cabin. The belt system consists of a metal net 21
supported and moved by rollers whose axles 22 rest in bearings at
both ends. The axles are driven by motor units 23 at such a speed
that it takes approx. 7 minutes for a carcass placed on the belt 21
at one end of the cabin to reach the opposite end of the cabin in
the scalded state.
As in FIG. 1, reference figures 4, 6, 7 and 9 designate a fan, a
gas burner, a water pump, and a water atomizer.
The embodiment shown in FIG. 3 is designed in a way similar to that
used in the apparatus of FIG. 2, but comprises three belt systems
30, 31, 32 instead of one. The length of the apparatus is approx.
10 meters and it is capable of scalding 320 carcasses per hour. The
belt systems are interconnected enabling each carcass to follow a
S-shaped path when being conveyed from the inlet of the upper
system 30 via system 31 to the outlet of the lower system.
The folding of the conveyor path means that the cabin is
considerably shorter and more economical as regards heat
consumption than the cabin type shown in FIG. 2. As in FIGS. 1 and
2 the reference figures 4, 6, 7 and 9 designate a fan, a gas
burner, a water pump and a water atomizer. They are used and
regulated in the same way in all the three embodiments.
Because of the simple regulation obtained by the thermostatically
controlled burner the carcasses will be swept constantly by air of
correct temperature and humidity. The burners are stepped down
automatically when the cabin is empty because it is only necessary
to compensate for the heat loss through the walls of the cabin. As
soon as the cabin is loaded with carcasses the cabin air is
immediately supplied with sufficient heat and humidity through
increased burner outputs controlled directly by the temperature
sensors.
* * * * *